charonn0 / RB-RC4

An RC4 implementation in Realbasic

RB-RC4

The RC4Stream class implements the RC4 stream cipher. RC4 is vulnerable to several forms of attack and generally should not be used to secure important data. In particular there is no authentication provided. Use at your own risk.

The RC4Stream.RandomBytes() method returns the specified number of bytes from the RC4 key stream.

The RC4Stream.Process() method combines the user-provided bytes with an equal number of bytes from the key stream, performing both encryption and decryption.

The RC4Stream.Offset property gets and sets the position in the key stream.

Example

Encrypt and decrypt a message:

  Dim message As String = "Attack at dawn!"
  Dim key As String = "seekrit"
  Dim rc4 As New RC4Stream(key)
  Dim ciphertxt As MemoryBlock = rc4.Process(message) ' encrypt
  rc4.Offset = 0 ' reset for decryption
  Dim cleartxt As String = rc4.Process(ciphertxt) ' decrypt

Generate random bytes:

  Dim key As String = "seekrit"
  Dim rc4 As New RC4Stream(key)
  Dim rand As MemoryBlock = rc4.RandomBytes(64) ' generate 64 pseudo-random bytes